Grinding machine



June 12,1945. w. J. BRYANT 2,378,127

GRINDING- MACHINE v Filed July 1, i943 s Sheets-Sheet 1 Patented June 12, 1945 UNITED- STATES. PATE Nrol-"FicE GRINDING MACHINE William J. Bryant, Springfield, vt assignorto Bryant chucking Grinder-Company, Springfield, Vt., a corporationpf Vermont Application July 1, 1943, Serial No.'493,032

6 Claims.

In grinding work-to a desired contour, it is well known that by relatively feeding. a contoured grinding wheel directly and without any lateralcomponent', sometimes termed a plunge or form grind, a better finish may be. obtained than when the desired contour is generated by form grinding, at least for the final finishing grinding, is preferable to-generating grinding. Where there is room to oscillate the grinding wheel, the grinding operation of such raceways has often been divided into two stages. the first of which comprises the roughing cut, accomplished by generationin one machine, followed by a finish forming grinding done in another machine. This, however, requires re-chucking of the work when changing from one machine to the other, and this necessitates that considera wheel having a traversing motion as well as a feeding motion. The raceways for ball bearings,

for example, should have a high finish, and hence operation may be tru ed during the time that the other wheel is in operation.

To these ends, as well as others which may appear, in accordance with this invention, thetwo grinding wheels,- one forrough grinding and the other for finish grinding, are secured to opposite ends of thesame spindle which is so mountedthat it may be turned end for end to present either selected wheel to the work;

able stock be left for removal in the finishing.

grinding to allow for unavoidable inaccuracies in there-chucking, and a finishing wheel best suitable for finishing is not well adapted to rapid removal of stock. To avoid this, it has also been proposed to rough and finish grind by the same wheel, the rough grinding being accomplished by generation and while using coolant, and the finishing grinding while the wheel oscillating means used during rough grinding is clamped, and by a forming cut without coolant. By cutting dry during the finishing forming cut, the action is softer than during the wet roughing out. Even with this change of conditions, however, the use of the same wheel for both roughing and finishing cuts does-not give the best results, as a grinding wheel most suitable for one of these operations is not the best suitedfor the other.

One object of the presentinvention, therefore,

is to provide a grinding machine. with both rough grinding and finish grinding wheels, the machine being so constructed that the particular wheel desired may be presented to the work in proper grinding relation thereto, and without rechucking and in which the change fromone to of Figure 3 on line 4-4 of Figure 2.

Still another object of the invention is to provide a spindle, mounting such that when the spindle is turned end for end, it is also in such position that the grinding wheels clear the truing device so that it is not necessary to move the truing device out of operative position when reversal of the spindle is to be effected.

For a more complete understanding of this in vention, together with further objects and advan'tageous constructions, reference may-be had to the accompanying drawings inwhich Figure 1 is a top plan view, somewhat diagrammatic, of a grinding machine embodying this invention.

Figure 2 is a fragmentary the same.

front elevation of Figure 3 is a detail sectional view to a larger scale on line 3-3 of Figure 1.

Figure 4 is a detail sectional view to the scale Figure 5 is a view similar to Figure 4, but showing the partsin different positions.

Figure 6 is a detailsectional view on line 6-4 of Figure 3.

Figures 7 and 8 are detail sectional views on lines-1-l and 8 8, respectively, of Figure '2.

Referring first to Figures 1, 2, 7 and 8, at l is indicateda bed of the grinding machine which is provided adjacent to its front and back edges with a pair of circular guide bars 2 secured thereto as by screws 2a. On these guide bars is slidably mounted a carriage 3 shown as provided with bearing shoes 4 slidably supported on the bars 2. This carriage 3 supports a cross slide 5 upon which is mounted a suitable work support ,6. As shown this work support carries a rotary work spindle I having on its outer end a pulley 8 by which it may be rotated and on its inner end, a work-holding chuck of any suitable description at 9.

Means may be provided for feeding the cross slide back and forth in the well knownmanner and to this end, a feed wheel I9 has been illustrated, this being connected to turn a splined shaft slidably mounted within a feed screw 9| having threaded connection with the cross slide 5.

- work, and means are therefore provided for 92 in contact with a former cam 93 carried b the carriage 3 by means of a weight 84 connected to the cross slide 5 through a, flexible connector 35 passing about a pulley 95, as shown in Figure 8. The former cam 93 may be moved on the carriage 3 relative to the cross slide 5 by means of hy- -draulic cylinder 91 to thus effect a transverse This cross slide is held with an abutment member may be accurately alined, adjusting screws 45 threaded through bars 46 permanently secured to carriage 3. Pipes l3 and I4 communicating with opposite ends of the cylinder l beyond the piston H are shown for the purpose of controlling the supply and discharge of fluid under pressure to cause the desired axial motion of the carriage 5. The formercam 93 as shown best in Figure l is tapered and may be moved axially to cause feed and retracting motion of the cross slide 5 as by a hydraulic pressure cylinder 91 having a piston 98 connected to the former cam.

Likewise carried by the bed I is a support l5, this being shown in Figure '7 as fixed to the bed I as by ears l5 integral with the support I5 bolted to inwardly directed flanges H on the bed I.

r This support l5, as shown best in Figures 3 to 5, is

provided with an upright cylindrical portion 20 within whichis slidably mounted a sleeve portion 2| depending from a grinding wheel turret 22. .As shown the portion 2| is integral with the turret. This turret 22 has an integral upstanding side piece 23 for engagement with the base .24 of a grinding wheel spindle carrier 25, and this carrier 25 may be held against the undercut surface of the portion 23 by means of a member 26 having a beveled edge 21 mating the beveled edge28 on the wheel carrier 25. This member 26 may be secured to the turret 22 by means of screws 30, thus to clamp the spindle carrier 25 in position thereon.

The spindle carrier 25 has journaled therein the grinding wheel spindle'35 having a pair of grinding wheels 36, 36a, one secured at each end there'- oi. The spindle support 25 may be provided with any suitable means for rotating the spindle 35. For example, it may comprise the stator of a motor of which a portion of the spindle 35 forms the rotor.

The turret 22 is permitted an axial up and down motion by reason of the slidable mounting of the sleeve 2| in the support l5, and when it is at'its upper limit of motion, it is also permitted a rock ing motion through substantially a 180 angle so as to permit end to end reversal of the spindle 35, thus to present either selected of the wheels 35 and 36a toward the work carried by the work holder 3. One of the wheels 3511 may be especially suitable for rough grinding and the other 5 especially suitable for finish grinding. When the turret isin its downward position, it is in proper relation for a grinding operation on tle G ing the turret against rotation when it is in this downward position. To this end, oppo ite sides of the base portion of the turret 22 are shown as beveled as at 46 and thesebeveled p rtions, when theturret is in its lowered position, as shown in Figure-4, engage oppositely beveled surfaces 4| of a pair of locating and locking strips 42. These strips 42 are secured as by screws face of the s pport 26 and in order that they 43 to theupper the upper face of the support 20, engage the strips 42 adjacent to opposite end portion thereof.

When the turret is lifted into the position as to present the desired wheel 36 or 35a toward Y the work. The lifting of the turret is shown as produced by fluid pressure. To this end, the sleeve portion 2| has extended thereinto a hollow rod 45, the upper end-of which is provided with a piston 45 which bearsagainst the inner wall of the sleeve to form a pressure chamber between it and the upper end of the sleeve, into which fluid under pressure may be passed or from which fluid pressure may be discharged through a pipe 41 secured to the lower end of the rod 45. As shown this rod 45 has a head 48 at its lower end engaged by a cover plate 49 closing off the lower endof a cylindrical portion 50 of the support 25, and the rod 45 has a lower reduced diameter end portion threaded for the reception of a nut 5| engaging a washer 52 which bears against the lower face of the cover plate 49. The turret is normally pressed downwardly into locating 'engagement with the strips 42, not only by its own weight, but as shown, by a coil spring 55 reacting between the lower face of the piston 45 and the top face of a washer 56 interposed between it and an annular plate 51 secured to the lower end of the sleeve 2|.

Intermediate to the end portions of the sleeve 2| it is provided with a portion" 50 of circular periphery provided with gear teeth 5| forming a. partial pinion with which mesh teeth '62 on a cylindrical rack bar 63 mounted for axialimotion in a bore 64 in the support l5. This rackbar 53 is in the form of a piston rod having a piston 69 (see Figures 3 and 6) riding in a. cylindrical bore 55 of the support i5, which bore forms a hydraulic cylinder closed off at its outer end by a cylinder head 65. By motion back and forth of the piston 54 and the rod 63, it will be evident that the sleeve 60, together with the turret carrying the wheel spindle, may be rocked through 180 in one or the other direction thus to reverse the spindle 35 end for endto present either selected of the two wheels into operative relation to the work. In order to accurately define the limits'of this turning motion, adjustable screw stops 51 and 68 may be employed, the stop 51 extending through a plate I0 closing off the inrod 53 is movable, and the stop 68 being carried by the cylinder head 65. Suitablepressure and discharge pipe connections at 12 and 13 permit the admission and discharge of fluid under pressure from opposite sides of the piston 64 as desired in order to move the rack bar 63 in the desired direction.

The arrangement of the two wheels on opposite ends of the spindle also makes feasible the truin of that wheel out of operative relation to the work while the other wheel is operating on the work, so that no time is lost from grinding due to truing, and the lifting of the spindle from grinding position before it is reversed end for ,end may be utilized to clear the wheels from thetruing mechanism, so that it is unnecessary to retract the truing mechanism from truing position to permit such reversal to be effected. This is shown best in Figures 1, 2 and 'I. The truing device shown in these figures is supported by a post 8| rising from a turntable 82 iournaled on an upright pivot bolt", and supported through a thrust ball bearing 84 from a cross feed slide 85 carried by a longitudinal slide 88, mounted on a portion 81 proiecting upwardly from the wheel support 15. Any suitable means such as is well known in the art may be provided for adjusting the slides 85 and 86 so as to present the truing tool at the proper position to true the wheel which is on that end hold said turret in either of two angular positions,

Gil

of the spindle remote from the work at any particular time. As shown such adjusting means may be actuated by turning the'vernier knobs 88 and 89, respectively. As shown the truing device is arranged to true the wheel edge to convex contour as by rogking the turntable, which may be done by moving the turret handle 90 between the two dotted line positions shown in Figure 1. Such a wheel edge contour is useful, for example, in grinding the raceways for ball bearings.

From an inspection of Figure 7, also, it will be seen that when the spindle carrier 25 is lifted to its upper position, shown in broken lines, ready to be turned to reverse the spindle end for end, the trued grinding wheels are in the dotted line position of Figure 7 where they clear the truing device so that removal'or retraction of the truing or dressing mechanism is not required to permit I ,this change of grinding wheels by reversing the spindle end for end.

in one of which one of said wheels is presented toward said work holder and in the other of which the other of said wheels is presented'toward said work holder, means for moving said turret axially into and out of said one position, means effective when said turret is out of said axial positionto,

rotate said turret from one to the other of said angular positions, and means for relatively moving said work holderand spindle to present a grinding wheel turned toward the work holder by said rod riding within said sleeve, 8- sprin surrounding said rod and reacting between a por-" tion of said support and said piston and normally In operation the work carriage being retracted and with-the roughing wheel extending toward the work support 6, the slide 5 being retracted and a work piece to be ground being in position in the work support, the work carriage 8 is advanced toward the wheel by motidn of the piston H until the roughing Wheel 6018 in proper axial relation thereto. While the wheel is being rotated the work slide 5 is fed by axial motion of the former cam 83. relative to the 0: 8 slide 5 on the carriage 3, which is moved by the piston and hydraulic cylinder 91 carried by the work carriage 3 to effect a rough forming cut.

When the work has been ground to the desired depth, during which time the finishing grinding wheel 38 may be trued by the truing device actuated by moving the handle 90, the work' cross slide 5 is backed on by reverse motion of the former cam 93, after which the work carriage 3- is retracted and the wheel spindle turned end for end to present the finish grinding wheel 36 toward the work. The work carriage 3 is. thereupon moved axially of the work to bring the work opposite to the finish grinding wheel 36, after which by moving the former cam, the cross slide 5' is moved to feed the 'work to the finish grinding wheel. After suiiicient finish form grinding and during which the rough grinding wheel may be trued, ,the cross slide 5 is again retracted to clear the wheel,-after which the slide 3 is retracted 1 and the finishe'd work piece removed and replaced by an unground piece ready for the start of the next cycle with the spindle reversed end for end holding said. turret in one axial position, means holding said turret in either of two angular positime when in the axial position to which it is urged by said spring, a rotary grinding wheel spindle carried by said turret, a wheel on each end of said spindle, one of said wheels being presented toward the work when said turret is in one of said angular positions and the other of said wheels being presented towardthe work when said turret is in the other of said angular positions, said sleeve having teeth out into its periphery, a

rack bar mounted for axial motion in said sup port and engaging-said teeth, means for moving said rack bar axially when said turretis moved from said held position to thereby turn said turret to change from one to the other of said grinding wheels presented toward the work, and means for moving said work holder and support relatively to cause the wheel so presented to operate on work carried by said work holder'or to be retracted therefrom.

3. A grinding machine comprising a bed, a work holder carried by said bed, a support carried by said bed, a turret on said support mounted for raising and lowering and for rocking motion, said turret having oppositely disposed beveled surfaces,

, locating bars carried by said support and provided with oppositely beveled surfaces for cooperation with the beveled surfaces of said turret whensaid turret is in its lowered position tohold said turrot is in the other of said angular positions, means for lifting said turret out of its lowered position '60 into, a position in which it isiree to be turned to presentthe rough-grinding wheel: 36a for the nrst-grinding action on the work piece.

- modifications might be made without departing from the spirit or scope of this invention.

l 2-claim: v .1. A grinding machine comprising a bed, a wor vret in either selected of two angular positions, a

rotaryspindle carried by said turret, a grinding -wheel on each end of said spindle. one of said.

grinding wheels being presented toward said work holder when said turret is in one of said angular positions and the-other of saidgrinding'wheels being presented toward thework when said turfrom one to the other ofsaid angular positions, means for turning said turret fromone to'the other of said angular positions when said turret holder carried by said bed, a support carried by said bed, a turret pivotally carried by'said support and mounted for motion axially-of said pivot, elements on, said support and turret cooperating when said turret is inoperative axial position to is in lifted position, and means for relatively movpresented toward 'said workholder to grind work held by said work holder. .4. A grinding machine'comprising a bed, a tary work holding chuck carried by. said bed,

grinding mechanism including .a rotaryispindl e also carried by said bed, a grinding wheel on each end of said spindle, means supportingsaid spindle for reversal end for end to selectively present said-work-holderand turret when said turret is in lowered position to cause the-grinding wheel either selected or said wheels into operative relation to work carried by said chuck, whereby said wheels may be presented successively to the work piece while said work piece remains chucked, a

tapered former cam arranged lengthwise oi the axis of rotation of said chuck, means for moving said cam lengthwise, and operative connections between said cam and chuck causing said movement of said former cam to move said chuck transverse to its axis to efiect feed and retraction between that wheel in operating position at any one time and work carried by said chuck.

5. A grinding machine comprising a bed, a

grinding mechanism including a rotary spindlespindle is in said definite position, said spindle when out of said position being cleared from said device tor such end for and turning by the transverse motion of said spindle away from said deflnite position.

6. A grinding machine comprising a bed, a turret pivotally and axially movable with respect to said bed, a grinding wheel spindle'carried by said turret and extending transverse to the pivotal axis of said turret, means holding the said turret against turning and in either of two angular positions with said spindle in reversed and to end relation when said spindle is in one axial position, said turret being free to be turned when said turret is in another axial position, and a wheel truing device carried by said bed in position to true one or the other of said wheels when said turret is in said one axial position depending upon the end for end position of said spindle, said turret when in said other axial position holding said wheels in cleared relation to said truing device for end to end reversal of said spindle.

WILLIAM J. BRYANT, 

